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<h1>Slow download speeds </h1>
<p>If you experience slow downloads, it could be for many reasons. However, 
	they can be different when you experience slow download speed from certain
	user(s) or when you get slow speeds downloading from every peer. Please try 
	to download from or get filelist of several (at least 10) users before you go on.
	Note that this faq does NOT cover the case when your downloads won't start at all.</p>
	
<h2>Slow downloads from certain user(s)</h2>
<p>This can happen for the following reasons :</p>
<ol>
 <li>The upload bandwidth of the person(s) you're downloading from is
 maxed out. Don't pay attention to the value of the 
 <a href="window_hub.html#userlistcolumns">Connection</a>
 column in the user's list, it's completely subjective and often is not a true reflection
 on the person's connection type since they can set it. 
 </li>
 <li>The peer you're downloading from is too far from you (maybe in another
 continent) and there's too many <a href="http://www.webopedia.com/TERM/H/hop.html"
 target="_blank" class="external">hops</a> in the connection between you and your peer.
 Its also possible that either your ISP or the other user's provider has
 limited overseas bandwitdh available. 
 You can check what country your peer is from in the <i>IP</i> column of the 
 <a href="window_connections.html">Connections window</a> 
 if the <a href="settings_appearance.html#guessip">Guess user country from IP</a> setting
 is enabled in the <a href="settings_appearance.html">Appearance</a> settings panel.
  </li> 
 <li>The person who you are downloading from is using a bandwidth
limiter. There are two types of limiting: client based or using a third-party
program. 
    <ul>
      <li>Clients with bandwith limiting capability often have set download
and upload speed ratios in place to avoid abuse. (ex. if the
upload speed limit is set below 6 KiB/s, then the client will restrict
the client download speed to a 2:1 ratio). This varies from
client to client and obviously not all support upload limiting.
This type of speed limiting <i>only</i>
restricts the uploading of files, including user lists. It
does not limit chat, private messages, or searches. From version 0.760
DC++ also has internal file transfer limiting capability. If enabled, DC++ shows
the upload limiting rate in the 
<a href="window_hub.html#userlistcolumns">Connection coloumn</a>
of a hub's user list. Other (older) clients may show this value in
L: or B: part of the <a href="faq_plusplus_tag.html">DC++ tag</a>.
</li>
      <li>Users could also be using a third-party program to limit the
speed of traffic. This type of speed limiting is absolute; it
will limit the speed of all traffic by the user, which can include file
transfers, searches, chat, and private messages. This type
of application never enforce a download speed:upload speed ratio, it
may be more prone to abuse.</li>
    </ul>
   So for particularly slow transfers (1 KiB/s or slower) from a certain user,
abusive upload limiting <b>may</b> be to blame. 
 </li> 
 <li>The person who you are downloading from suffers from one or more  
 constant speed problem described in the next section.
 </li> 
</ol>
<p>Solution : try to find more sources for your downloads :</p>
<ul>
 <li>
 To gain more possible sources for your download select your download either in 
 the <a href="window_download_queue.html">Download Queue</a> or in the
 <a href="window_downloads.html">Downloads window</a>. Then use the rightclick
 function <i>Search for alternates</i> to see if there are other users have
 the file shared. In the slots column of the <a href="window_search.html">
 Search results window</a> you can find users with fewer slots used 
 <i>may</i> result in faster speeds - someone 
 with two out of three (2/3) slots free may have more bandwidth available 
 than someone with one out of three (1/3).</li>
 <li>
 More sources for queued files can be discovered and automatically added if you enable
 <a href="settings_queue.html#automatchqueue">Automatically Match Queue for Search Hits</a>
 in Queue settings.</li>
 <li>
 Automatic discovery for additional sources is also possible if you enable
 <a href="settings_queue.html#autosearchdl">Automatically Search for Alternative Download Locations</a>
 in Queue settings. Note that some hubs have
 predefined minimum search interval rules so enabling this function may
 result no hits for manual searches in these hubs.
 </li>
 <li>
 To minimize the download time make sure you have checked 
 <a href="settings_advanced.html#segmented">Enable segmented downloads</a> in
 Advanced settings. With segmented downloads enabled
 you are able to download the pieces of a file from several sources at the same time.
 </li>
</ul>

<h2>Slow downloads from every user</h2>
<p>If you experience constant slow downloads with DC++ this can be for one or more of the following reasons :</p>
<ol>
  <li>You have enabled <a href="settings_bwlimit.html">bandwith limiting</a> for downloads.
  Make sure the limiter is disabled or set to high enough value.</li>
  <li>Your Internet connection is shared with others on your <acronym
 title="Local Area Network">LAN</acronym> and they are using up all the
available bandwidth. Tell them to knock it off. =) 
  Also your connection speed to the gateway or router on your <acronym
 title="Local Area Network">LAN</acronym> can be slower than the available speed
 from your <acronym title="Internet Service Provider">ISP</acronym>. 
 It could be for reasons like week signal strength on a wireless connection, 
 broken/old network devices, etc... Try to do a file transfer test within your local
 network to be sure that it's fast enough.</li>
  
  <li>Your ISP may be limiting your P2P traffic via some method of
packet shaping. Call up the ISP and inquire if they do anything
with P2P traffic. You can try to connect to ADC hubs and test your downloads there.
As ADC is a newer and more efficient DC protocol it can be still unknown to your ISP's
throttling system. If the ISP <i>does</i>
throttle you, then there is nothing much that can be done to increase the
speeds. This is also common at Universities and at the workplace,
and is <a href="faq_university.html">the topic of another FAQ</a>.</li>

  <li id="ddos">You haven't set up your third party firewall or internet monitor
software correctly. Some of these security applications may treat p2p transfer as a 
<a href="http://en.wikipedia.org/wiki/Denial-of-service_attack" target="_blank"
 class="external"> DDoS flood</a> attempt and tries to defend your computer from it.
Try to disable or even uninstall these applications temporarily and test your downloads again.
If it helps refer the application's documentation how to make exception rules for DC++.
If you have a router its also possible that it has some anti-DDoS or flood protection
feature and it may enabled by default. Check the router's documentation or configuration page
for a possible option of this kind.</li>

<li>You need to optimize your operating system for your current
connection speed. First, <b>close <u>all</u></b> <acronym
 title="peer to peer">P2P</acronym> applications. Next run the <a
 href="http://www.dslreports.com/tweaks" target="_blank" class="external">DSLReports
TweakTest</a>. Once you have optimized it, then run a speed test at
<a href="http://www.dslreports.com/stest" target="_blank" class="external">DSLReports
SpeedTest Page</a> or at the nice looking
<a href="http://speedtest.net" target="_blank" class="external">SpeedTest.Net</a> page
(select a test site closest to your location for
accurate results). This will give you a good idea what your
maximum download and upload speeds are. If you're getting within
10% of your connection speed, that's the best you can get! If you
are having trouble with your <i>broadband</i>
connection, and it relates to packet loss, excessive latency, or
Internet or <acronym title="Internet Service Provider">ISP</acronym>
congestion, running the <a href="http://www.dslreports.com/linequality"
 target="_blank" class="external">Line Quality Test </a>
may help find the cause (<i>requires logon, free signup).</i>
  </li>

    <li><p>Your Internet connection is <acronym
 title="Digital Subscriber Loop">DSL</acronym>, cable, or satellite one
with an asymmetrical connection speed, such as 768/128 Kib/s or
3.0 Mib/s / 256 Kib/s. On such connections, if you upload near the speed of
your upload limit (16 KiB/s in the case of the 768/128 connection), it
may affect the speeds of your downloads, no matter how much larger
your download connection is. If this is happening, you can use the 
<a href="settings_bwlimit.html"> built-in transfer limiting function</a>
to set the maximum upload rate value <b>slightly</b> lower than
your available upload speed (eg. to 15 or 14 KiB/s in the case above).</p>
<p>If you aren't allowed to use upload limiting you can also experiment with changing the
size of <a href="settings_expert.html#writebuffer">Socket Write Buffer</a> in Experts Only
panel of DC++ settings. It defaults to 8 KiB and you can try to change it to a smaller
value. You should specify the value in bytes and you may have to try several values
to test what size suits your connection best. Note that you should restart DC++ to
changes take effect.</p></li>

  <li>Your copy of Windows XP, Vista or Windows 7 has the "<acronym
 title="Quality of Service">QoS</acronym> Packet Scheduler"
enabled so you are not able to use some reserved bandwidth for download. Follow <a
 href="http://kb.earthlink.net/case.asp?article=23629"
 target="_blank" class="external"> this guide</a> to disable QoS in XP or
 <a href="http://www.vistax64.com/tutorials/109326-qos-bandwidth-reserve-limit.html"
 target="_blank" class="external"> this one</a> to disable QoS in Vista or Windows 7.
Windows 2000 does not come with QoS. Some routers also have QoS capabilities, 
but shouldn't be enabled by default. Please consult your router's manual for more
information. </li>

  <li>Your computer is infected with malicious software which altered the low level network
settings of your operating system. This is common when your Windows become infected with spy/adware.
Even they are disinfected, their destructive modifications usually still remain. You can
follow the official guided help from Microsoft how to restore these settings 
<a href="http://support.microsoft.com/kb/299357" target="_blank" class="external">here</a> and
<a href="http://support.microsoft.com/kb/811259" target="_blank" class="external">here</a>.</li>
</ol>
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